City of Boulder/USGS Water Quality Monitoring
Water Quality Index for May, 2006 at
Boulder Creek at Orodell

Grade A For May, 2006 the WQI rating at Boulder Creek at Orodell (BC-ORO) was Excellent (A) due to a WQI value of 92.50. The chart below details the WQI calulations at this site. See the detailed explanation of the WQI method for more information.


Parameter Unit Parameter Value Q-value Weight Factor Total
DO% % sat 104.20 98.68 0.17 16.77
Fecal Coliform #/100 mL Data Unavailable
pH pH 7.15 90.66 0.11 9.97
Total Phosphate mg PO4/L 0.04 97.26 0.10 9.73
Nitrates mg NO3/L Data Unavailable
Turbidity NTU 5.40 84.10 0.08 6.73
Total Solids mg/l 93.00 83.23 0.07 5.83
Totals (factors, total) 0.53 49.03
Adjusted WQI 92.50

The WQI is computed by converting measured Water Quality Parameters to "Q-Values" using charts developed by the National Sanitation Foundation (NSF) water quality scientists. The Q-Values are then multiplied by a weighting factor based on the importance of that water quality parameter. These values are totaled and then divided by the sum of the weight factors.

WQI at Upstream Station: North Boulder Creek at Boulder Falls

WQI at Downstream Station: Boulder Creek at Eben G. Fine Park

WQI for April at this station

WQI for June at this station

Return to WQI map for May


Thank You! BASIN was a community project which benefitted from over 1000 hours of public volunteer time. BASIN was highlighted by the US EPA in a national case study in its 2001 handbook Delivering Timely Environmental Information to Your Community. Thank you to all volunteers, and especially to the late Jim Waterman, BASIN Project Coordinator!

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Last Page Update - Thursday March 01, 2007